Java 复制文件和目录

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.RuntimeException;
public class Copy {
    private static void copyFile(File from, File to) {
        System.out.println("开始拷贝文件：" + from.getAbsolutePath() + " --------> " + to.getAbsolutePath());
        byte buf[] = new byte[1024];
        int count = 0;
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            bis = new BufferedInputStream(new FileInputStream(from));
            bos = new BufferedOutputStream(new FileOutputStream(to));
            if (bis != null && bos != null) {
                while ((count = bis.read(buf)) != -1) {
                    bos.write(buf, 0, count);
                    bos.flush();
                }
            }
        } catch (IOException e) {
            throw new RuntimeException("文件复制异常！", e);
        } finally {
            try {
                if (bis != null)
                    bis.close();
                if (bos != null)
                    bos.close();
            } catch (IOException ex) {
                throw new RuntimeException("文件关闭失败！", ex);
            }
        }
    }
    private static void copyDir(File fromDir, File toDir) {
        if (!toDir.exists()) {
            toDir.mkdirs();
        }
        File[] files = fromDir.listFiles();
        for (File f : files) {
            if (f.isFile()) {
                File t = new File(toDir, f.getName());
                if (confirmRewrite(t)) {
                    copyFile(f, t);
                } else {
                    continue;
                }
            } else if (f.isDirectory()) {
                if (f.getName().equals(toDir.getName())) {
                    continue;
                }
                copyDir(f, new File(toDir, f.getName()));
            }
        }
    }

    private static boolean confirmRewrite(File to) {
        if (to.exists()) {
            System.out.print("文件已经存在，是否覆盖?[y|n]:");
            char confirm;
            try {
                confirm = (char) System.in.read();
                System.in.skip(System.in.available());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            if (confirm == ‘y‘)
                return true;
            else
                return false;
        } else {
            return true;
        }
    }
    public static void main(String args[]) {
        if (args.length != 2) {
            System.err.println("Arguments num error!");
            System.err.println("usage:java Copy " + "from  to");
            return;
        }
        File from = new File(args[0]);
        File to = new File(args[1]);
        if (!from.exists())
            throw new RuntimeException(new FileNotFoundException("文件或目录不存在！"));
        /*
         * 目的地存在的话，如果是文件，则源地址也必须是文件；如果目的地是目录，源地址可以是文件，也可以是目录。
         */
        if (to.exists()) {
            // 如果目的地址存在
            if (to.isFile() && from.isFile()) {
                if(confirmRewrite(to)){
                    copyFile(from, to);
                }else{
                    return;
                }
            } else if (to.isDirectory()) {
                if (from.isFile()) {
                    File temp=new File(to, from.getName());
                    if(confirmRewrite(temp))
                        copyFile(from, temp);
                } else {
                    copyDir(from, to);
                }
            } else {
                throw new RuntimeException(new IOException("不允许将目录复制到文件!"));
            }
        } else {
            // 如果目的地址不存在
            if (from.isFile()) {
                copyFile(from, to);
            } else {
                to.mkdirs();
                copyDir(from, to);
            }
        }
    }
}